Gas turbine engine with improved afterburner

ABSTRACT

The disclosure shows an afterburner for a gas turbine engine comprising fuel injectors and concentric, annular, V-shaped gutters which function as flameholders. The fuel injectors are mounted in cantilever fashion from a casing and their inner ends are connected by links to a ring to damp vibrations.

United States Patent Arand [451 June 20, 1972 [54] GAS TURBINE ENGINEWITH IMPROVED AFTERBURNER [72] Inventor: John K. Arand, Palos VerdesPeninsula,

Calif.

[73] Assignee: General Electric Company [22] Filed: June 29, 1970 [21]Appl. No.: 50,415

[52] vU.S. Cl. ..60/261, 60/3972 R, 60/39.74 R [51] Int. Cl ..F02k 3/10[58] Field ofSearch .....60/26l, 39.72 R, 39.74R

[56] References Cited UNITED STATES PATENTS 2,714,287 8/1955 Carr..60/261 X 2,934,891 5/1960 Brown ..60/261 2,975,589 3/1961 Vdoviak..60/261 3,056,261 10/1962 Krabacher et al... 3,315,468 4/1967 Vdoviak..60/39.72

FOREIGN PATENTS OR APPLICATIONS 821,286 10/1959 Great Britain ..60/39.72

Primary Examiner-Allan D. Hermann AttorneyDerek P. Lawrence, Frank L.Neuhauser, Oscar B. Waddell, Joseph B. For-man and Edward S. Roman [57]7 ABSTRACT The disclosure shows an afterbumer for a gas turbine enginecomprising fuel injectors and concentric, annular, V-shaped gutterswhich function as flameholders. The fuel injectors are mounted incantilever fashion from a casing and their inner ends are connected bylinks to a ring to damp vibrations.

3 Claims, 5 Drawing Figures P'A'TENTEDaunzo m2 3 670 501 sum 2 or 2INVENTOR. JOHN K. ARAND ATTOINIV GAS TURBINE ENGINE WITH IMPROVEDAFI'ERBURNER The invention described and claimed in the United STatespatent application herein resulted from work done under United StatesGovernment contract FA4S-66-6. The United States Government has anirrevocable, non-exclusive license under said application to practiceand have practiced the invention claimed herein, including the unlimitedright to sublicense others to practice and have practiced the claimedinvention for any purpose whatsoever.

The present invention relates to improvements in gas turbine engineshaving afterburners for augmenting the energy level of a hot gas streamto be discharged from a propulsion nozzle.

In such afterbumers, fuel is injected into a hot gas stream to increase,or augment, its energy level. Flameholders are mounted immediatelydownstream of the injectors to establish a stable flamefront orlocalized combustion zone for the augmenting fuel.

Afterburner fuel injectors are desirably elongated tubes or tube bundlesmounted in cantilever fashion on an outer casing. Their length isnecessitated by the need to distribute fuel through the full height ofthe annular stream. Because of their length and cantilever mounting,they have been particularly prone to induced vibration which can resultin high stresses and premature failure. The desire for avoidingcomplexity and maintaining light weight motivates against the use ofsuch obvious expedients as increased sizing of the injectors orsupporting their opposite ends in overcoming this problem.

Accordingly, the object of the invention is to minimize vibration ofafterburner fuel nozzles in a non-complex fashion involving minimumweight.

These ends are broadly attained by the use of a damper ring tied to theinner ends of cantilevered fuel injectors, preferably by linkage means.

The above and other related objects and features of the invention willbe apparent from a reading of the following description of thedisclosure found in the accompanying drawings and the novelty thereofpointed out in the appended claims.

In the drawings:

FIG. 1 is a schematic showing of a gas turbine engine incorporating anafterbumer for supersonic propulsion;

FIG. 2 is a partial longitudinal section showing the afterbumer ingreater detail;

FIG. 3 is a section taken on line III-III in FIG. 2;

FIG. 4 is an enlarged section of a portion of FIG. 2; and

FIG. 5 is a section taken on line V-V in FIG. 4.

FIG. 1 schematically illustrates a gas turbine engine of the typeemployed for supersonic flight. Air enters an inlet comprising a spikeand is then compressed in an axial flow compressor 12. This compressedair supports combustion of fuel in a combustor 14 to generate a hot gasstream. The hot gas stream drives a turbine 16 which in turn, through ashaft 18, powers the rotor of the compressor 12. The energy level of thehot gas stream may then be augmented by the combustion of further fuelin an aftcrburner or augmenter 20. The augmented gas stream is thendischarged from a variable area, convergent-divergent nozzle 22 toprovide the necessary thrust for supersonic flight.

In subsonic flight operation, the hot gas stream may or may not beaugmented in the afterbumer and the nonle may be adjusted to other thanthe illustrated convergent-divergent configuration.

Referencing FIGS. 2 and 3, it will be noted that the hot gas stream hasan annular flowpath as it enters the afterburner. This flowpath isdefined by an engine casing 24 and a central plug 26 which is supportedon appropriate frame structure (not shown).

The afterbumer includes fuel injectors 30 and flameholders in the formof annular V-shaped gutters 32. Each injector comprises a plurality oftubes 33 which are longitudinally aligned and progressively shorter in adownstream sense. Openings in the tubes spray fuel into the hot gasstream and a stabilized flamefront or combustion zone is maintained bythe gutters 32. This type of an afterbumer combustion mechanism is knownper se.

The gutters 32 are mounted in a manner more fully described and claimedin my copending application, Ser. No. 40,298, filed May 25, 1970, and ofcommon assignment with the present application. Briefly, each gutter 32is connected to a plurality of angularly spaced beams 34 by links 36.The outer ends of the beams are pivotally mounted on the casing 24 withthe links 38 pivotally connecting the inner ends of the beams to thecasing 26.

The tubes 33 of each injector are held together by straps 40. The outerends of the tubes 33 project beyond the casing 24 and are mountedthereon by a bracket 42. The outer ends of the tubes 33 are connected toa suitably controlled source of pressurized fuel.

The injectors 30 thus project in cantilever fashion, angled in adownstream direction, from the casing. The inner ends of these injectorsare tied together by a damping ring 44. More specifically, the inner tiestraps 40 are extended in an upstream direction to pivotally mount links46 on pins 48. The opposite ends of the links 46 are pivotal on pins 50which are mounted on lugs 52 projecting from the ring 44.

The damping means thus provided efiectively prevents vibration beinginduced into the cantilevered fuel injectors. Further, this end isaccomplished with a minimum of weight and complexity.

Various modifications of the preferred embodiment, herein described,will appear to those skilled in the art within the spirit and scope ofthe present inventive concepts which are to be derived solely from thefollowing claims.

Having thus described the invention, what is claimed as novel anddesired to be secured by Letters Patent of the United States is:

1. A gas turbine engine comprising an afterburner for increasing theenergy level of a hot gas stream, said afterburner including an outercasing,

a plurality of elongated fuel injectors mounted on said casing andprojecting inwardly therefrom in cantilever fashion, said fuel injectorsbeing angularly spaced around said casing, and

means for damping said injectors including a ring tied to the severalinjectors adjacent their free, inner ends.

2. A gas turbine engine as in claim 2 wherein:

the damping means includes a linkage connection between each injectorand said ring.

3. A gas turbine engine as in claim 2 wherein:

the injectors comprise a plurality of tubes aligned in a longitudinaldirection with the tubes having a progressively shorter length in adownstream direction and straps holding the tubes in assembled relationand the linkage connections comprising upstream extensions of the innerinjector straps, links pivotally mounted thereon, and lugs projectingdownstream from said ring and pivotally receiving the upstream ends ofsaid links.

1. A gas turbine engine comprising an afterburner for increasing theenergy level of a hot gas stream, said afterburner including an outercasing, a plurality of elongated fuel injectors mounted on said casingand projecting inwardly therefrom in cantilever fashion, said fuelinjectors being angularly spaced around said casing, and means fordamping said injectors including a ring tied to the several injectorsadjacent their free, inner ends.
 2. A gas turbine engine as in claim 2wherein: the damping means includes a linkage connection between eachinjector and said ring.
 3. A gas turbine engine as in claim 2 wherein:the injectors comprise a plurality of tubes aligned in a longitudinaldirection with the tubes having a progressively shorter length in adownstream direction and straps holding the tubes in assembled relationand the linkage connections comprising upstream extensions of the innerinjector straps, links pivotally mounted thereon, and lugs projectingdownstream from said ring and pivotally receiving the upstream ends ofsaid links.